PubMed Health⌕ Search

Biomedical subjects

J P Hanker

Publications and source records attributed to J P Hanker.

14 recordsLinked to original sources
PubMed1979

Suppression of prolactin secretion by lisuride throughout the menstrual cycle and in hyperprolactinaemic menstrual disorders.

Normally menstruating volunteers as well as patients with hyperprolactinaemic menstrual disorders were treated with lisuride hydrogen maleate (200 micrograms b.i.d.), an ergoline derivative with dopaminergic properties. Within 3 h after an oral dose of 200 micrograms lisuride, PRL levels decreased significantly in all subjects to a plateau which lasted up to 3 h. Thereafter a gradual increase of serum PRL was noted. In the normally menstruating volunteers lisuride treatment did not result in any significant change of gonadotrophin or of sex steroid secretion, while both, basal as well as metoclopramide (MTCL) stimulated PRL release were significantly diminished. The inhibition of PRL secretion in patients with short luteal phases resulted in an increase of luteal progesterone output. In both treated groups ovulation occurred 1 to 5 days earlier in cycles on lisuride than in control cycles. LF-RH/MTCL tests performed in the patient bearing a pituitary prolactinoma before and after lisuride treatment revealed a continuous increase of pituitary LH pools, while PRL secretion decreased under lisuride therapy. Subsequently ovulation and menstruation occurred. The data presented demonstrate that lisuride is a potent inhibitor of PRL secretion and has proven its clinical usefulness for treatment of hyperprolactinaemic menstrual disorders. Application of lisuride resulted in an increase of luteal progesterone secretion in previously demonstrated corpus luteum insufficiency as well as in restoration of normal cyclical feedback mechanisms in tumorous hyperprolactinaemic anovulation. The MTCL-PRL stimulation test is suitable to monitor PRL suppression during lisuride treatment, while LH-RH testing reveals the effectiveness of lisuride by demonstrating an increase of pituitary gonadotrophin pools.

Adenoma↗
PubMed1978

Dose-response study with a new LH-RH analogue, D-Ser (TBU)6 LH-RH 1-9 (EA)10 during the follicular phase of the menstrual cycle.

D-Ser (TBU)6 LH-RH 1-9 (EA)10 (HOE 766) a highly active LH-RH analogue, was studied with regard to its effects on the release of follicle stimulating hormone (FSH), luteinizing hormone (LH) and oestradiol-17beta (Oe2) during the follicular phase of the menstrual cycle. Forty-two regularly menstruating women were allowed to five different treatment groups with different doses (1.25 microgram; 2.5 microgram; 5.0 microgram; 10.0 microgram; 20.0 microgram) of HOE 766 given as intravenous bolus injections and the plasma concentrations of FSH, LH and Oe2 were measured up to 24 h after injection using specific radioimmunoassays. In the majority of cases, peak values of both FSH and LH occurred 4 h after injection being significantly different from pre-injection levels (P less than 0.02 in the 1.25 microgram treatment group, P less than 0.005 for the other treatment groups). Statistical analysis of maximum values as well as the absolute and relative increase in the different treatment groups revealed a dose-dependent effect of HOE 766. Maximum values of Oe2 occurred 8 h after injection and were found to be significantly different from pre-injection levels (P less than 0.005). However, no dose dependent effect was observed. It was concluded that HOE 766 is a potent and long-acting stimulator of FSH, LH and OE2 release in women. The effect of HOE 766 is dose dependent for FSH and LH but not for Oe2.

Adult↗
PubMed1978

Effects of cimetidine on prolactin, LH, and sex steroid secretion in male and female volunteers.

The histamine H2-receptor antagonist cimetidine, which has recently been introduced for the treatment of gastric and duodenal ulcers and haemorrhage, respectively, stimulates prolactin (PRL) secretion. The release of PRL after a bolus injection of the compound is significantly higher in female than in male volunteers, and is more pronounced during the luteal than during the follicular phase of the menstrual cycle. Oral administration of the drug stimulates PRL to a similar extent as parenteral administration. Treatment of male and female volunteers with cimetidine for 20 days (1 g/day orally) resulted in elevated serum PRL concentrations in both sexes. Basal LH levels as well as the response to 25 microgram LH-RH were not significantly changed after treatment. Testosterone levels in males and oestradiol levels in females were not altered. Luteal progesterone, however, was significantly diminished in the menstrual cycles when cimetidine was given. The mechanism underlying the stimulatory effect of cimetidine on PRL secretion is not clear, but it does not seem that this ability is exerted via an inhibition of pituitary dopamine receptors. The dopaminergic effect of lisuride, an ergot alkaloid, could not be reversed by cimetidine.

Adult↗
PubMed1978

Gonadotrophin release during chronic administration of D-ser (TBU)6 LH-RH-EA in functional amenorrhoea.

Six women with long-standing functional amenorrhoea were treated with 5 microgram of D-Ser (TBU)6 LH-RH-EA twice daily for 14 days. The functional states of the gonadostats, as assessed by a 25 microgram LH-RH test dose, varied widely before the treatment was started whereas at the end of it they were uniformly low. In all patients D-Ser (TBU)6 LH-RH-EA induced gonadotrophin release, the peak values occuring between day 1 and 3 of therapy. Despite further injections mean gonadotrophin levels declined rapidly therafter and remained in the basal range for the rest of the study. Release of oestradiol was very uncharacteristic. No consistent ovarian response pattern was observed during the analogue administration. It is obvious that chronic stimulation with D-Ser (TBU)6 LH-RH-EA leads to a decreased responsiveness of the pituitary gland.

Adult↗
PubMed1977

Prolactin oversuppression.

Patients with primary infertility due to hyperprolactinemic corpus luteum insufficiency and oligomenorrhea were treated with Bromocriptin. Suppression of serum prolactin for up to four menstrual cycles resulted in a normalisation of the length of the cycle(32 vs 28 days) as well as of luteal progesterone secretion. In addition, ovulation occurred earlier after than before treatment (on day 14 vs day 18). When, however, prolactin concentrations reached levels of less than 120 muU/ml (3 ng/ml), which were observed during the 5th and 6th treatment course, reappearance of shortened luteal phase occurred probably due to oversuppression of prolactin. Premenstrual spottings were observed too. The data presented indicate that minimal prolactin is required for normal follicular maturation and luteal development. On the other hand, the gonadostat may be susceptable to the dopaminergic stimulus of Bromocriptin to a different extent as oversuppression of prolactin is not observed in hyperprolactinemic anovulatory syndromes. Thus, treatment with Bromocriptin requires a continuous monitoring of serum prolactin as well as individual treatment regimens.

Bromocriptine↗
PubMed1977

Reduced 'gonadotrophin response to releasing hormone' after chronic administration to impotent men.

Ten endocrinologically normal men with secondary sexual impotence were given 500 microng LHRH subcutaneously every 8 h. After 4 weeks treatment the LH response to 500 microng LHRH was reduced from a peak of 35.7+/-5.2 to 16.8+/-3.5 mu/ml (P less than 0.01) and the FSH response from 4.2+/-0.93 to 2.39+/-0.4 mu/ml (P greater than 0.01). Circulating total testosterone, oestradiol, prolactin and sex hormone binding globulin showed no significant changes. Whether this inability of the pituitary to maintain it s response to LHRH is peculiar to impotent men requires further study.

Adult↗
PubMed1976

A double blind cross over trial of gonadotrophin releasing hormone (LHRH) in sexually impotent men.

A double blind cross over trial of 500 mug of gonadotrophin releasing hormone or placebo subcutaneously every 8 h for 4 weeks in ten men with secondary sexual impotence is reported. No obvious clinical improvement occurred but statistical analysis of a libido score showed some overall improvement, especially the spontaneous occurrence of erections during the treatment period (P LESS THAN 0-05).

Adult↗
PubMed1975

Inhibition of the plasma-aldosterone response to frusemide by bromocriptine.

The administration of the long-acting dopaminergic agonist bromocriptine to five healthy volunteers inhibited the rise in plasma-aldosterone that normally follows the administration of frusemide. This inhibition was not due to a lowering of plasma-renin activity. It is suggested that dopamine may modulate the normal secretion of aldosterone either directly, or indirectly, possible by inhibition of prolactin secretion.

Aldosterone↗