Influence of 2 Br-α-ergocryptine (CB 154) on the secretion of prolactin, LH, FSH and testosterone and on testicular growth in rams subjected to different photoperiods

Ravault, J.P.; Barenton, Bruno; Blanc, Michel; Daveau, Agnès; Garnier, Danielle Hélène; Ortavant, R.; Pelletier, J.; Reviers, M. de; Terqui, M.

doi:10.1051/rnd:19820710

Cited by 10 publications

(11 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The mechanism of this effect is unclear: bromo¬ criptine treatment has been reported to stimulate FSH release in sheep (Ravault et al, 1982), but no such effect was seen in the present study (Fig. lb).…”

Section: Discussioncontrasting

confidence: 66%

Preliminary studies of the effects of bromocriptine on testicular regression and the spring moult in a seasonal breeder, the male blue fox (Alopex lagopus)

Smith¹,

Mondain-Monval²,

Simon³

et al. 1987

Reproduction

View full text Add to dashboard Cite

Bromocriptine administration in the form of slow-release injections to male blue foxes during March-May abolished the normal spring rise in plasma prolactin concentrations seen in May and June. The spring moult was prevented and the treated animals retained a winter coat of varied quality and maturity until the end of the study in August. Plasma testosterone concentrations fell normally from March until August. Testicular regression was, however, delayed, although there were individual variations in response. Estimation by DNA flow cytometry in early July of the relative numbers of haploid, diploid and tetraploid cells in the testis showed that, in the treated animals, 74-80% of the cells were haploid (maturing germinal cells), 4-6% tetraploid (mainly primary spermatocytes) and the rest diploid cells (somatic cells and the remaining germinal cell types). In the control males, however, no haploid cells were detected and the majority of cells were diploid (93-99%). At castration in August, histological examination revealed various stages of testicular regression in the treated and control animals.

show abstract

Section: Discussioncontrasting

confidence: 66%

Preliminary studies of the effects of bromocriptine on testicular regression and the spring moult in a seasonal breeder, the male blue fox (Alopex lagopus)

Smith¹,

Mondain-Monval²,

Simon³

et al. 1987

Reproduction

View full text Add to dashboard Cite

show abstract

“…(1) Land, Carr, McNeilly & Preece (1980), Ravault, Barenton, Blanc et al (1982) and Schanbacher (1980) failed to alter gonadal activity under long days by sup¬ pressing prolactin secretion through administration of bromocriptine to ewes, and (2) the present results revealed that the gonadal activity in response to long days was not necessarily reciprocal to prolactin secre¬ tion in SCGX goats. It is likely, therefore, that melatonin mediated the response of gonadal function and prolactin secretion to long days independently.…”

Section: Discussioncontrasting

confidence: 62%

Superior cervical ganglionectomy prevents gonadal regression and increased plasma prolactin concentrations induced by long days in goats

Maeda¹,

Mori²,

Kano³

1986

Journal of Endocrinology

View full text Add to dashboard Cite

The effects of the abolition of the diurnal change in melatonin secretion on the photoperiodic response of the gonadal axis and prolactin secretion to long days were examined in female goats. Female Saanen goats, reared under short-day conditions (8 h light: 16 h darkness; lights on at 05.00 h) at 22 +/- 2 degrees C for 5 months, were bilaterally superior cervical ganglionectomized (SCGX). One month after surgery, both SCGX and intact control goats were divided into two groups. Animals in group 1 were maintained under short days and those in group 2 moved to long days (16 h light: 8 h darkness; lights on at 05.00 h). In group 1, both SCGX and intact goats ovulated periodically and basal plasma prolactin levels were maintained throughout the day. In intact controls, exposure to long days suppressed ovulation and increased prolactin secretion for the first 150-200 days of exposure. The animals became photorefractory after this time; ovulation recurred and prolactin secretion returned to basal levels. Superior cervical ganglionectomy abolished or weakened the suppression of gonadal function and eliminated the increase in prolactin secretion induced by exposure to long days in the intact controls. These results suggest that the pattern of melatonin secretion under long days is necessary to induce the photoperiodic response of gonadal function and prolactin secretion to long days and that, under natural conditions, melatonin regulates the seasonal changes in gonadal function and prolactin secretion by mediating the effect of long days.

show abstract

“…In some species such as the rat and the ram, the injection of bromo¬ criptine into normal animals does not induce changes in reproductive function (Skett, Eneroth & Gustafsson, 1978;Poindron, Cognie, Gayerie et al 1980;Doherty et al 1981), but delays puberty in immature female rats (Shaban & Terranova, 1986). In contrast, admin¬ istration of bromocriptine to hyperprolactinaemic animals induces changes in sexual function which dif¬ fer according to species: testosterone concentrations are decreased and LH concentrations increased in the golden hamster (Bex, Bartke, Goldman & Dalterio, 1978), LH concentrations are decreased without changes in testosterone concentrations in the ram (Ravault, Barenton, Blanc et al 1982), and LH con¬ centrations are increased in the rat (Doherty et al 1981). In fact, two systems for the regulation of pro¬ lactin secretion and its relationship with reproductive functions seem to be implicated: the first one under photoperiodic control and the second depending on stress factors including pheromonal effects ).…”

Section: Discussionmentioning

confidence: 89%

Role of prolactin in a pheromone-like sexual inhibition in the male lesser mouse lemur

Perret¹,

Schilling²

1987

Journal of Endocrinology

View full text Add to dashboard Cite

Sexual activity of the male lesser mouse lemur can be induced by a long photoperiod, and plasma testosterone concentrations increase from 20 to 220 nmol/l within 3 weeks of photoperiodic stimulation. When isolated males were exposed to the volatile compounds from the urine of an active dominant male for 4 weeks at the beginning of the long daylight period, they demonstrated a significant decrease in testosterone concentrations (134 +/- 11 nmol/l) compared with controls (210 +/- 26 nmol/l) within 2 weeks. Lowering concentrations of prolactin by daily injections of bromocriptine prevented the decrease in testosterone in males simultaneously exposed to the odorant stimulation. Increasing concentrations of prolactin by daily injections of sulpiride mimicked the effect of the odorant stimulation in males receiving only fresh non-odorized air. The decrease in testosterone was strengthened when sulpiride was administered concurrently with exposure to urine. These results support the conclusion that variations in the concentration of prolactin are involved in the neuroendocrinological process mediating the pheromone-like sexual inhibition in the male lesser mouse lemur. However, daily injections of bromocriptine in males which were photoperiodically stimulated but not exposed to dominant male urine odour, also induced a significant decrease in testosterone concentrations. This finding suggests that two different systems involving prolactin and leading to opposite effects might be implicated in the regulation by environmental factors of sexual activity in the male lesser mouse lemur.

show abstract

Influence of 2 Br-α-ergocryptine (CB 154) on the secretion of prolactin, LH, FSH and testosterone and on testicular growth in rams subjected to different photoperiods

Cited by 10 publications

References 4 publications

Preliminary studies of the effects of bromocriptine on testicular regression and the spring moult in a seasonal breeder, the male blue fox (Alopex lagopus)

Preliminary studies of the effects of bromocriptine on testicular regression and the spring moult in a seasonal breeder, the male blue fox (Alopex lagopus)

Superior cervical ganglionectomy prevents gonadal regression and increased plasma prolactin concentrations induced by long days in goats

Role of prolactin in a pheromone-like sexual inhibition in the male lesser mouse lemur

Contact Info

Product

Resources

About