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Biomedical subjects

G Lafuenti

Publications and source records attributed to G Lafuenti.

11 recordsLinked to original sources
PubMed1988

Relationship between maternal parity, basal prolactin levels and neonatal breast milk intake.

Basal serum levels of prolactin (PRL) in 21 nursing mothers were measured by radioimmunoassay on the 2nd, 3rd and 4th days of the puerperium. The quantity of breast milk suckled during the 4th day of life was also evaluated by calculating the difference in the baby's weight before and after each feeding. During the first postpartum days, mean basal levels of PRL did not change. However these levels were noted to be significantly lower in the multiparas (p less than 0.05) than in the primiparas. In addition, the milk intake in neonates of multiparous mothers was significantly greater (p less than 0.05) than that in neonates of primiparous mothers. The author's hypothesis, based on the results of animal experimentation described in the literature, is that initiation of breast-feeding is facilitated in multiparas by the increased number of occupied PRL receptors in the mammary glands reflected by the lowered serum levels of the hormone.

Female↗
PubMed1979

Presence of positive feedback between oestrogen and LH in patients with Klinefelter's syndrome, and Sertoli-cell-only syndrome.

In five adult patients with Klinefelter's syndrome and two with Sertoli-cell-only syndrome, exogenous administration of 17 beta-oestradiol, resulting in a sustained and prolonged elevation of circulating oestrogen levels, had a biphasic effect on LH release. After an initial decrease, a dramatic rise in peripheral levels of LH (positive feedback) was observed in all patients. The timing and magnitude of the induced LH surge was similar to that observed in postmenopausal women after administration of large doses of Ethinyloestradiol. A similar positive feedback effect on the secretion of FSH could not be demonstrated. In two patients with the Sertoli-cell-only syndrome, oestrogen treatment induced marked variations in serum testosterone levels, which appeared to be related to the LH changes. Similar changes were not present in patients with Klinefelter's syndrome, indicating a decrease in the sensitivity of the testicular Leydig cell. These experiments demonstrate that positive feedback between oestrogen and luteinizing hormone is present in the adult human male.

Adult↗
PubMed1975

Enchancement of deficient pituitary response to luteinizing hormone releasing hormone in patients with primary amenorrhea.

Although the absence of pituitary response to the luteinizing hormone releasing hormone (LHRH) test has been considered proof of a lesion primarily localized at the pituitary level, the possibility exists that an absent pituitary response may represent only the effect of a chronic deficiency of hypothalamic secretion. To verify this hypothesis, 4 patients with primary amenorrhea, hypogonadotropic hypogonadism, and deficient or absent responses to a 25 mug LHRH rapid IV test were treated with 400 mug LHRH infused in 7 hours during each of 3 successive days. The finding that patients with deficient LH responses to a rapid LHRH test became normally responsive to a second equivalent test after a slow and prolonged treatment with the decapeptide suggests that, in these patients, besides a lesion at the pituitary level, a primary defect at the hypothalamic or higher centers may also be suspected.

Adolescent↗
PubMed1975

[Gonadotropins].

The clinical usefulness of plasma LH and FSH radioimmunoassays, both in basal and dynamic conditions, is briefly discussed. While occasional LH and FSH determinations may indicate only a serious gonad failure, at least when high values are found, dynamic studies before and after LH-RH i.v. injection may suggest a hypothalamic or pituitary lesion. In this regard the LH-RH test is presented as the most evident demonstration of the utility of gonadotropin radioimmunoassay. Different patterns of response are presented and their correlation with menstrual disorders is discussed in view of different distribution (Tab.1). Moreover, the AA. suggest a primary hypothalamic deficiency in LH-RH in the cases of "deficient" response that, being a constant finding in different days, became a "normal" response after 3 days therapy with LH-RH infusion and returned to basal levels 2 months later. Equally, an "exaggerated" response consistenly found in some patients with secondary amenorrhea, is suspected to be of hypothalamic origin since "normalization" may be obtained after a similar LH-RH treatment.

Amenorrhea↗
PubMedDate not supplied

Effects of estrogen on the release of gonadotropins and prolactin in male pseudohermaphrodites.

Three adult patients with male pseudohermaphroditism were given 15 microgram/kg body weight of 17 beta-estradiol im daily (at 08:00 hours) for 12-15 days and circulating levels of gonadotropins, prolactin and estradiol were determined by radioimmunoassay before and during the steriod course. All patients had elevated gonadotropin levels prior to starting on estradiol. During estrogen treatment all patients demonstrated suppression of FSH and LH with a subsequent rise in LH (positive feedback) while estrogen levels remained elevated. A similar positive feedback effect on the secretion of FSH could not be demonstrated. In two patients, who had never received estrogen treatment prior to this study, estradiol induced a significant elevation of serum prolactin levels within 24 h and levels remained higher than basal values for the rest of the estrogen treatment period. In the third patient, who had been previously treated with estrogen, serum prolactin levels did not change significantly during estrogen treatment. This study was afforded evidence for the presence in humans of an estrogen mediated LH release concomitant with an augmented prolactin secretion.

Adolescent↗