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At least 19 recordsLinked to original sources
PubMed1979

Pituitary hormones and amnesia.

Pituitary hormones profoundly influence behavior through direct actions on the brain. One of these behavioral effects is the attenuation of experimental amnesia. Traditionally, amnesia is considered as a "loss of memory." Memory comprises at least 2 stages: input (memory consolidation) and output (memory retrieval). Theoretically, disturbance of either aspect of memory may be the cause of amnesia. Also, it is possible that amnesia is based on a factor or factors not related to memory. Data and theories on amnesia in man were reviewed. Some salient features were mentioned: (1) amnesia can be induced by a variety of agents; (2) amnesia covers periods ranging from seconds to years; (3) amnesia gradients can be established; (4) amnesia is to a large extent reversible. From this survey, it seems possible that amnesia is not a homogeneous phenomenon and that even in one person a disturbance of both memory consolidation and memory retrieval may be produced by one and the same event. Animal studies in general have confirmed these conclusions. We have developed an animal model in order to study the effects of pituitary peptides on amnesia. This model is based on CO2-induced amnesia for a one-trial passive avoidance response in rats. This amnesia could be attenuated by treatment with ACTH-analogs 1 hour before the retrieval test. This anti-amnesic effect of ACTH-analogs was not dependent on the nature of the behavioral response or the amnesic treatment. The vasopressin-analog DGLVP similarly exerted an anti-amnesic effect when injected before the retrieval trial. In contrast to ACTH-analogs, however, it also reduced the amnesia when injected before acquisition. These results suggest that amnesia may comprise a "faulty-consolidation" and a "faulty-retrieval" component, which may be amended by different pituitary hormones. The study of the anti-amnesic activity of peptides therefore not only serves to characterize the nature of the behavioral effect of these peptides but may also prove to be helpful of the unraveling of processes involved in amnesia.

Adrenocorticotropic Hormone↗
PubMed1979

The influence of bromocriptine on serum levels of growth hormone and other pituitary hormones and its metabolic effects in active acromegaly.

The effect of treatment with bromocriptine for 12--18 months on serum GH and metabolic responses was studied in sixteen patients with active acromegaly. Of this group ten patients showing a sustained GH reduction of more than 50% during an 8 h bromocriptine test, proved to be responsive to long-term therapy. In the responding patients GH levels decreased to 38% of the pretreatment level after 12 months of therapy. A dose higher than 10 mg did not produce a significantly greater effect. Prolactin and LH levels decreased in all patients, FSH levels showed a significant rise. Testosterone levels in the male patients increased significantly, indicating that the state of hypogonadism can at least be partially reversed. The GH levels became normal in only one patient. We conclude that the role of bromocriptine in acromagaly is limited and selective pituitary operation and/or irradiation is preferred as definitive treatment in most patients.

Acromegaly↗
PubMed1978

On the isolation of human pituitary hormones.

Six human pituitary hormones can be obtained from a single batch of human pituitary glands by the procedure described. Starting from an acetone powder of the glands, the hormones are segregated into three fractions; one containing GH and PRL, a second containing the glycoprotein hormones, and the third fraction containing smaller peptides including ACTH and MSH. Clinical grade GH is extracted from the residue at alkaline pH, followed by a series of ammonium sulfate and pH fractionations. Further chromatography on G-100 yields a highly purified GH preparation. FSH is purified by chromatography on carboxymethyl cellulose at pH 5.4 followed by gel filtration on G-100 and fractionation on sulfopropyl Sephadex C-50 at pH 5.4. LH and TSH are separated by DEAE-cellulose chromatography at pH 9.5. The GH and glycoprotein hormones are recovered in a highly purified form and good yields. The GH is obtained in an active form which is easily soluble and well suited for clinical use. A large part of the PRL is also saved during the extraction procedure.

Adrenocorticotropic Hormone↗
PubMed1978

Antigenic activity and mobility of bovine pituitary hormones.

The antigenic activity and mobility of bovine pituitary hormones; follicle stimulating hormone (FSH), growth hormone (GH), luteinizing hormone (LH), thyroid stimulating hormone (TSH), adrenocorticotropic hormone (ACTH) and melanophore stimulating hormone (MSH) were studied with the aid of agar gel diffusion and electrophoresis. MSH and ACTH were the only hormones not demonstrating antigenicity. Tests by electrophoresis showed "gamma" mobility of the pituitary hormones exhibiting antigenic activity. The observation of antigenic determinants exhibiting identity with immunoglobulins suggests that the bovine pituitary gland houses immunoglobulin molecule and the various pituitary hormones.

Adrenocorticotropic Hormone↗
PubMed1979

Secondary structure prediction of anterior pituitary hormones. Lack of correlation between predicted values and circular dichroism data.

The secondary structures of human somatotropin, human choriomammotropin, ovine and porcine prolactin, human, ovine and porcine beta-lipotropin, human and ovine lutropin, human thyrotropin, human corticotropin, alpha-melanotropin and human beta-melanotropin have been predicted by the method of Chou & Fasman. Predicted contents of alpha-helix and beta-sheet do not correspond well with values estimated from circular dichroism spectra.

Adrenocorticotropic Hormone↗
PubMed1977

Growth rate and secretion of pituitary hormones in relation to age and chronic treatment with thyrotropin-releasing hormone in prepubertal dairy heifers.

Holstein heifers were treated with synthetic thyrotropin-releasing hormone (TRH) or saline twice daily from one week through 6 mo of age. Plasma concentrations of prolactin (PRL) and thyrotropin (TSH) were elevated (P less than .01) within 30 min after the first TRH injection (1 week of age). At 1 and 3 mo of treatment, PRL and TSH increased in response to TRH, although the TSH response was reduced (P less than .01) as compared to the first day of treatment. Although plasma growth hormone (GH) appeared to be elevated following the first TRH injection, this effect was not statistically significant (P less than .05), nor was it significantly influenced by treatment following subsequent TRH injections. None of the 3 hormones, PRL, TSH or GH, was elevated following the final TRH injection at 6 mo of age. In contrast, plasma concentrations of PRL and TSH were increased in a control heifer injected with TRH at 6 mo. These data indicate that hormonal responsiveness to TRH stimulation decreases with continued twice daily treatment at doses of TRH used in the present studies. Examination of weight gains indicated that chronic treatment with TRH was associated with increased growth rate through 6 mo of age (10.6% increased average daily gains P less than .10), which was exhibited in a steeper slope (P less than .05) of the growth curve in the TRH group. Feed intake was slightly greater in TRH heifers, although feed efficiency (kg feed/kg gain) was not different between the two groups. Plasma concentrations of PRL increased (P less than .01) with age (r = +0.938) in control heifers while plasma TSH and GH were not significantly related to age. This observation establishes a positive correlative relationship between PRL secretion and the approach of puberty in the dairly heirfer. It was also noted that elevation of PRL secretion by TRH treatment was associated with significant advancement of age at first observed estrus (9.4 vs. - 10.5 mo) suggesting that a functional relationship between PRL secretion and puberty may exist in dairy heifers.

Aging↗
PubMed1978

Effect of pituitary hormones on dentin production in maxillary incisors in the rat.

The effect of pituitary hormones on dentin production and longitudinal growth of the maxillary incisors in normal and hypophysectomized rats was investigated. Bovine growth hormone was found to increase the dentin production slightly in normal rats and significantly in hypophysectomized rats. Other pituitary hormones showed no effects on dentin apposition in the doses and periods tested. The effects of the pituitary hormones on the longitudinal growth of the tooth were small or insignificant. The effects of growth hormone on the dentin apposition and the longitudinal growth of the tooth after hypophysectomy were smaller than the effects on longitudinal bone growth and cortical bone remodeling, indicating different sensitivity to hormones between different mineralized tissues.

Age Factors↗
PubMed1977

The combined effect of growth hormone and methandrostenolone on the linear growth of patients with multiple pituitary hormone deficiencies.

Six patients with multiple pituitary hormone deficiencies (MPHD) were initially treated with separate courses of methandrostenolone and growth hormone and later with the two drugs combined. During the basal period the mean growth velocity was 2.8 cm/year. Methandrostenolone alone, 0.02-0.05 mg/kg/day given to four of the patients led to an acceleration of the growth velocity to a mean of 5.0 cm/year, while growth hormone 6 mg/week alone accelerated the growth rate to a mean of 6.0 cm/year. Combined therapy led to a striking increase in the mean growth rate to 9.3 cm/year. The shortcoming of the combined growth hormone-androgen therapy was the fast acceleration in skeletal maturation even after short-term administration.

Adolescent↗
PubMed1978

Importance of pituitary hormones in aetiology of diabetic ketoacidosis.

The role of pituitary hormones in the aetiology of diabetic ketoacidosis was examined by withdrawing insulin from five pituitary-ablated diabetics for a 12-hour period. The rise in blood glucose and ketone-body concentrations was markedly retarded in these patients when compared with five matched juvenile-type diabetic controls with normal pituitary function. When cortisol replacement in the pituitary-ablated patients was increased to reproduce the high plasma concentrations found in severe ketoacidosis, blood ketones and glucose were increased but were still significantly lower than in the control diabetics. It is concluded that pituitary hormones may be important in the development of diabetic ketoacidosis.

Adult↗
PubMed1976

Delayed pituitary hormone response to LRF and TRF in patients with anorexia nervosa and with secondary amenorrhea associated with simple weight loss.

The qualitative and quantitative responses of LRF-induced LH and FSH release and TRF-induced TSH and Prolactin (PRL) release were evaluated in 21 patients with anorexia nervosa, 19 patients with secondary amenorrhea associated with simple weight loss (SWL) who did not fulfill the psychologic criteria for anorexia nervosa, and 7 normal women in the early follicular phase of the menstrual cycle. Basal plasma LH and FSH were significantly lower in the anorexia nervosa group compared to the SWL group and normals (P less than 0.05). The LRF-induced integrated LH responses, however, were the same in the 3 groups and the integrated FSH responses were greater in the underweight groups when compared to normal. The time of the peak LH response (mean+/-SE) was signifantly delayed (P less than 0.01) in both the anorexia nervosa (49 +/- 6.1 min) and SWL (28 +/- 2.5 min) groups when compared to normal (17 +/- 2.3 min). The time of the FSH response was significantly delayed (P less than 0.05) in anorexia nervosa (95 +/- 9.6 min) when compared to normals (35 +/0 7.9 min) and SWL patients (62 +/- 11.7 min). Normal basal TSH and PRL and normal peak TSH and PRL responses to TRF were found in anorexia nervosa. The time of the TSH and PRL peak (56+/-8.9 and 36+/-3.6 min,, respectively) in anorexia nervosa was significantly later than normal (26 +/- 1.7 and 36 +/- 3.6 min respectively) (P less than 0.01). It is concluded that despite normal quantitative response to releasing hormones, there are abnormally delayed responses in both anorexia nervosa and SWL patients. The SWL responses were intermediate between those of the anorexia nervosa group and normals. The constellation of normal quantitative but abnormal kinetic LRF and TRF responses supports the hypothesis that the endocrine changes seen in anorexia nervosa are consistent with hypothalamic dysfunction.

Adolescent↗
PubMed1979

Effects of cimetidine on the secretion of some pituitary hormones.

Cimetidine infused intravenously into 6 healthy volunteers did not induce significant changes in plasma levels of prolactin (hPRL), thyreotropin (hTSH), gonadotropin (hLH and hFSH) and growth hormone (hGH). Conversely it caused a significant increase in prolactin response to TRH without modifying the hTSH response to thyreotropin-releasing hormone (TRH) and gonadotropin response to gonadotropin-releasing hormone (GnRH). Data obtained in these experiments, together with data reported in the literature, suggest that the amplified prolactin response to TRH observed during cimetidine infusion, is likely to be connected with a blockade of H2-receptors rather than to unspecific actions of cimetidine.

Adult↗
PubMed1978

Dopamine affects basal and augmented pituitary hormone secretion.

Although the role of the neurotransmitter, dopamine (DA), in the regulation of PRL has been well documented, controversy exists regarding its participation in the regulation of the other pituitary hormones. Consequently, we infused DA into six healthy male subjects (ages 19-32) and studied its effects on both basal pituitary hormone levels and augmented hormonal release induced by insulin hypoglycemia (ITT), TRH, and gonadotropin-releasing hormone (GnRH). DA alone produced a modest though significant increase in GH concentration from 2.2 +/- 0.5 to 11.9 +/- 3.7 ng/ml (P less than 0.05) by 60 min, but the peak incremental GH response to ITT was significantly inhibited by DA (43.5 +/- 5.0 vs. 16.3 +/- 3.3 ng/ml; P less than 0.01). PRL concentrations fell during the DA infusion (20.4 +/- 3.0 to 10.6 +/- 1.5 ng/ml; P less than 0.02) at 235 min, and the PRL responses to both ITT and TRH were completely abolished. Although the basal LH and FSH concentrations were unaffected by DA, the incremental LH response to GnRH was inhibited (45.5 +/- 10.6 to 24.4 +/- 5.4 mIU/ml; P less than 0.05), while the FSH response was unchanged. DA significantly reduced the basal TSH concentration from 3.9 +/- 0.2 to 2.5 +/- 0.2 micro U/ml (P less than 0.01) at 230 min and blunted the peak incremental TSH response to TRH (6.0 +/- 1.5 vs. 2.9 +/- 0.9 microU/ml; P less than 0.01). DA had no effect on basal cortisol levels, the cortisol response to ITT, basal plasma glucose, or the degree of hypoglycemia after ITT. Our data provide new evidence that DA has an inhibitory as well as a stimulatory role in the regulation of GH secretion in normal humans. It inhibits centrally as well as peripherally mediated PRL secretion and blunts the LH response to GnRH. In addition, DA lowers both basal and TRH-mediated TSH release, confirming the reports of other investigators.

Adult↗