Effects
of aproteic diet on hypothalamic-pituitary- gonadal regulation
in the male rat. Osvaldo J. Ponzo, Dora Rondina,
Berta Szwarcfarb, Silvia Carbone, Jaime Moguilevsky & Pablo
Scacchi*
Abstract:
The effect of an aproteic diet (Ap) on the reproductive axis
in young male rats was studied. Also the refeeding effect at
different times after the aproteic diet was studied.
The Ap diet was given during 21 days. In refeeding groups, the
control diet was given during 2, 4 and 6 weeks after the aproteic
diet. We studied the plasmatic testosterone, luteinizing hormone
(LH) and follicle stimulating hormone (FSH) levels. Also the
hypothalamic GnRH concentration and in vitro hypothalamic GnRH
secretion in basal and induced condition was studied.
The total protein deficit produced significant reduction in
body, testis, seminal vesicles and prostate weights. This was
accompanied with decreased levels of plasmatic testosterone
(P<0.02). In this aproteic group there was a significant
reduction in LH (P<0.05) and FSH (P<0.05) plasmatic levels.
Refeeding with control diet reversed this situation, producing
significant increment in LH (P<0.05) and FSH levels (P<0.01)
at the fourth and second weeks, respectively. The basal hypothalamic
GnRH secretion did not differ from the control; nevertheless
the induced secretion was significantly (P<0.05) greater
in the aproteic group. Also the hypothalamic GnRH concentration
was increased (P<0.05) in animals fed with the aproteic diet.
The minor testis, prostate, and seminal vesicles’ weight,
and a decreased plasmatic testosterone in rats fed with an aproteic
diet, are produced by a decrease in gonadotrophin secretion.
This decrease in turn is caused by a reduction in GnRH secretion,
since hypothalamic GnRH concentration is increased in rats fed
with the aproteic group, and induced secretion is greater in
this group. All these alterations produced by an aproteic diet
are reversible, since—with contol diet refeeding—the
gonadotrophin secretion returned at control levels.
