The acute asymmetric effects of hemiovariectomy on testosterone secretion vary along the estrous cycle. The participation of the cholinergic system

Abstract

The presence of asymmetry in the capacity of the left and right ovaries to secrete testosterone was analyzed by studying the effects of hemiovariectomy along the estrus cycle one hour after surgery. The effects of ether anesthesia on hormone serum levels were also analyzed. Bilateral ovariectomy and the extirpation of the left ovary performed on the day of proestrus resulted in significantly lower testosterone levels. Compared to the anesthetized group, the effects of perforating the peritoneum unilaterally varied according to the day of the estrous cycle and the side of the peritoneum surgery was performed on. Injecting atropine sulfate (ATR) to control or anesthetized rats on D1 resulted in a significant increase of testosterone serum levels. The effects of perforating the peritoneum on testosterone levels depended on the cholinergic innervation and varied along the estrous cycle. Blocking the cholinergic system before performing unilateral or bilateral ovariectomy had different effects depending on the day of the estrous cycle. Testosterone plasma levels increased significantly when surgery was performed on the day of diestrus and dropped when surgery was performed on proestrus. Similar effects were observed when the left adrenal was extirpated from animals with the cholinergic system blocked. The results presented herein support the hypothesis of asymmetry in the ovaries' abilities to secrete steroid hormones, and that the capacity to secrete testosterone varies along the estrous cycle.

Figure 1

Means ± s.e.m. of testosterone serum concentration (pg/ml) in rats with left (LPP), right (RPP) or bilateral (BPP) sham operation performed at 13.00 h on Diestrus 1, Diestrus 2 or Proestrus, sacrificed one hour after surgery. * p < 0.05 vs. diestrus 1, MANOVA followed by Tukey's t test; * p < 0.05 vs. control, Student's t test.

Figure 2

Effects of unilateral peritoneum perforation (panels A and B) black, unilateral ovariectomy (panel B) white, unilateral adrenalectomy (panel C) black, bilateral ovariectomy + left ovary extirpated (white), and (panel D) bilateral adrenalectomy + right ovary extirpated (white) performed at 13.00 h of the day of diestrus 1, on testosterone serum levels, measured 1 hour after surgery. * p < 0.05 vs. unilateral peritoneum perforation, Student's t test.

Figure 3

Effects of unilateral peritoneum perforation (panels A and B, black) unilateral ovariectomy (panel B, white), unilateral adrenalectomy (panel C, white) bilateral ovariectomy + left ovary extirpated and (panel D, white) bilateral adrenalectomy + right ovary extirpated performed at 13.00 h of the day of diestrus 2, on testosterone serum levels, measured 1 hour after surgery. * p < 0.05 vs. unilateral peritoneum perforation, Student's t test.

Figure 4

Effects of unilateral peritoneum perforation (panels A and B, black) unilateral ovariectomy (panel B, white), unilateral adrenalectomy (panel C, white) bilateral ovariectomy + left ovary extirpated and (panel D, white) bilateral adrenalectomy + right ovary extirpated performed at 13.00 h of the day of proestrus, on testosterone serum levels, measured 1 hour after surgery. * p < 0.05 vs. unilateral peritoneum perforation, Student's t test.

Figure 5

Comparative effects of atropine sulfate injection (black columns) to rats with unilateral peritoneal perforation (white) performed on diestrus 1 (D1), diestrus 2 (D2) or proestrus (P). * p < 0.05 vs. unilateral peritoneum perforation, Student's t test.

Figure 6

Comparative effects of atropine sulfate injection (black, red) to rats with unilateral ovariectomy (white) or unilateral adrenalectomy (yellow) performed on diestrus 1 sacrificed one hour after surgery. * p < 0.05 vs. unilateral peritoneum perforation, Student's t test

Figure 7

Comparative effects of atropine sulfate injection (black, red) to rats with unilateral ovariectomy (white) or unilateral adrenalectomy (yellow) performed on diestrus 2 sacrificed one hour after surgery. * p < 0.05 vs. unilateral peritoneum perforation, Student's t test

Figure 8

Comparative effects of atropine sulfate injection (black, red) to rats with unilateral ovariectomy (white) or unilateral adrenalectomy (yellow) performed on proestrus sacrificed one hour after surgery. * p < 0.05 vs. unilateral peritoneum perforation, Student's t test.