PubMed Health⌕ Search

Biomedical subjects

T Ranta

Publications and source records attributed to T Ranta.

At least 91 records · Page 5Linked to original sources
PubMed1979

Dual action of adrenergic system on the regulation of thyrotrophin secretion in the male rat.

The effect of graded doses of drugs modifying adrenergic activity on basal and cold-stimulated TSH secretion was studied in male rats. alpha-methyl-p-tyrosine (aMPT) (16 h before 30 min cold-exposure), phenoxybenzamine (1 h), Ca-fusarate (1 h) and diethyldithiocarbamate (DDC) (1 and 18 h) dose-dependently depressed the cold-stimulated TSH secretion. The effect of reserpine (24 h) was not significant. Clonidine (1 h), dihydroxyphenyl-serine (DOPS) (1 h), noradrenaline (NA) (1 h), and L-Dopa (1 h) were also effective in decreasing serum TSH levels, but dopamine (DA) (ad 2 mg/kg, 1 h) had no effect. Basal TSH levels were also decreased by various doses of clonidine, DOPS and NA, given ip 1 h before sacrifice. Clonidine (1 mg/kg), NA (1 mg/kg), DA (2 mg/kg), aMPT (300 mg/kg), phenoxybenzamine (2 or 20 mg/kg), Ca-fusarate (50 mg/kg) or L-Dopa (200 mg/kg) did not modify the TRH-induced TSH response. These results cannot be explained by assuming only a stimulatory function for the adrenergic system on the secretion of TSH in the rat. The site of the possible inhibitory function of noradrenaline in the control of TSH cannot be deduced from these results, but various possibilities are discussed.

Animals↗
PubMed1979

Effects of methylmercaptoimidazole (MMI), propylthiouracil (PTU), potassium perchlorate (KClO4) and potassium iodide (KI) on the serum concentrations of thyrotrophin (TSH) and thyroid hormones in the rat.

Male Sprague-Dawley rats were given graded doses of methylmercaptoimidazole (MMI), propylthiouracil (PTU), KClO4 or KI in drinking water for 4 days, or the lowest effective dose of each drug for various times. The rats were sacrificed at 1--2 p.m. and serum T3, T4 and TSH concentrations were measured by radioimmunoassays. It was found that administration of 5 mg/l of MMI, 10 mg/l of PTU and 100 mg/l of KClO4 for 4--14 days induced a transient rise in serum TSH and a fall in serum T3 or T4 or in both. The effects of KI were not consistent. In another series of experiments, PTU (10 mg/l) was given in drinking water for 4 days, and then graded doses of T3 or T4 were given iv, or 100 ng of TRH was injected into a tail vein, or the animals were exposed to 4 degrees C for 30 min. The initial high TSH levels were further increased by TRH and cold and decreased by T3 and T4. The PTU-treated animals had goitres after 4 days. We infer that low doses, that is to say 10--100 times lower than previously described, of antithyroid drugs induce a hypothyroidism characterized by an increased TSH level and a decreased serum T3 or T4 level or both. A 4 days' treatment with PTU (40 mg/l in tap water) is a suitable tool for studying the effect of various conditions on TSH secretion.

Animals↗
PubMed1979

Prolactin levels and bromocriptine treatment of short luteal phase.

Moderate hyperprolactinemia was found in 14 of 30 infertile patients with short luteal phase indicating a possible hypothalamic disorder in these patients. While the cycle length was normal, 28 days, late ovulation around day 18 of the cycle was characteristic of these patients. During bromocriptine treatment, 2.5 mg twice daily, ovulation took place earlier and luteal phase became longer irrespective of the basal serum prolactin level. The mean (+/- SEM) duration of luteal phase was 9.9 +/- 0.2 days in control cycles, and 11.7 +/- 0.5 and 12.2 +/- 0.3 days in two successive bromocriptine cycles (P less than 0.001). In patients taking bromocriptine, luteal phase became longer than 11 days in 37 of 60 treatment cycles, but no significant difference was recorded in the circulating progesterone and LH levels during mid- and late luteal phase. Three patients became pregnant and they all had normal baseline serum prolactin concentrations. Our results show that bromocriptine may be effective even when no apparent indication for prolactin suppression can be demonstrated.

Bromocriptine↗
PubMed1978

Effect of prostaglandin F2alpha on ovarian and pituitary function in the mid-luteal phase.

The effects of PGF2alpha infusion in a dose of 25 micrograms/min for 5 hours on serum levels of estradiol-17beta, progesterone, LH, FSH, TSH and prolactin, and on the pituitary hormone responsiveness to LRH and TRH were studied in 10 apparently healthy cycling women in the mid-luteal phase. No systematic alteration was seen in the pituitary and ovarian hormone levels during PGF2alpha infusion, and the pituitary hormone responses to releasing hormones were unaffected. Ovarian steroid production increased in response to increased gonadotropin levels after LRH injection during PGF2alpha administration. These results confirm that PGF2alpha is not luteolytic in humans and no apparent relationship between PGF2alpha and pituitary hormone secretion exists.

Adult↗
PubMed1978

Pyridoxine treatment of galactorrhoea-amenorrhoea syndromes.

The effect of pyridoxine (B6) on galactorrhoea, amenorrhoea, and the galactorrhoea-amenorrhoea syndrome was studied in 22 patients. No consistent change in serum prolactin concentration and no resumption of ovulation were seen during 3 months B6 therapy. Inappropriate lactation ceased in 3 of 10 patients with galactorrhoea alone, and menses were restored in 2 of 9 patients with the galactorrhoea-amenorrhoea syndrome while on B6 therapy. Our results suggest that B6 is not generally effective in the treatment of galactorrhoea-amenorrhoea syndromes.

Adult↗
PubMed1978

Serum and seminal plasma prolactin levels in oligospermia.

Prolactin concentration was estimated by radioimmunoassay in seminal plasma and serum of 26 oligospermic and 23 normospermic men. No significant difference was found in the mean serum prolactin concentration between normospermic and oligospermic subjects, but there was an inverse correlation between serum prolactin level and sperm count within the group of oligospermic patients. Although the mean prolactin concentration in seminal plasma of oligospermic group was somewhat lower than in the normospermic group the difference did not reach statistical significance, and no correlation was found between seminal plasma prolactin concentration and sperm count within either group.

Cell Count↗
PubMed1978

Pregnancy-specific beta-1-glycoprotein levels in cholestasis of pregnancy.

Plasma concentrations of pregnancy specific beta-1-glycoprotein (PSBG) were measured by specific radioimmunoassay in 211 samples from 123 normal women during the third trimester of pregnancy and in 166 samples from 68 patients with cholestasis of pregnancy. At 37--38 weeks of gestation patients with cholestasis had significantly lower PSBG levels than the normal pregnant women (P less than 0.005), whereas the levels in patients in the cholestasis had not been significantly different from those for normal pregnant women before 37 weeks. At 37--38 weeks of gestation patients with cholestasis showed a slight correlation between placnetal weight and plasma PSBS levels (r = 0.362; P less than 0.05), whereas this was not found in patients with normal pregnancy. No correlation was found between infant weight or length at birth and the PSBG concentrations in either group, and no difference was noted in PSBG concentrations between cases with and without fetal distress.

Cholestasis↗
PubMed1977

Evidence for dopaminergic control of thyrotrophin secretion in the rat.

The effects of two dopamine agonists (apomorphine and bromocriptine) and a dopamine antagonist (pimozide) on cold- or thyrotrophin releasing hormone (TRH)-induced TSH secretion were studied in normal male rats. Apomorphine given in various doses (0-5-10 mg/kg body wt) 10 min before exposure to cold significantly depressed TSH secretion. Large doses of bromocriptine (5-10 mg/kg body wt) given 1 h before exposure to cold, also blocked this response whereas a smaller dose (2-5 mg/kg body wt) given 30 min, 1, 3 or 6 h before cold exposure or repeated doses (0-1-2-5 mg/kg body wt) for 3 days did not modify cold-induced TSH secretion. Pimozide given in various doses (-25-2-5 mg/kg body wt) 1 h before exposure to cold did not alter the cold response, but 2-5 mg/kg reversed the inhibition caused by apomorphine or bromocriptine. None of these drugs affected TRH-induced TSH secretion. These results suggest that there are no dopaminergic receptors on the pituitary thyrotrophs, but that dopamine might be an inhibitory transmitter in the brain involved in the regulation of TSH secretion in the rat.

Animals↗
PubMed1976

Bromocriptine treatment of secondary amenorrhoea.

Bromocriptine 2-5 mg twice daily is effective in the treatment of both normoprolactinaemic and hyperprolactinaemic secondary amenorrhoea. This was demonstrated by the restoration of menstrual cycle and/or ovulation in 9 of 18 normoprolactinaemic and in 8 of 14 hyperprolactinaemic patients taking bromocriptine. Serum-prolactin level decreased in both groups of patients, and usually menstruation was recovered within 8 weeks'treatment. Galactorrhoea disappeared in 7 of 9 hyperprolactinaemic patients, and 2 became pregnant. After treatment had ceased spontaneous menstrual activity continued in 4 patients. 16 patients had side-effects the commonest being nausea and vertigo. These usually disappeared with the dosage was reduced, but 5 patients refused to continue. These results point to a new approach in the treatment of secondary amenorrhoea, even in those patients whose clinical findings give no indication of prolactin suppression.

Adolescent↗