Asymmetric steroidogenic response by the ovaries to the vasoactive intestinal peptide
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ORIGINAL ARTICLE
Asymmetric steroidogenic response by the ovaries to the vasoactive intestinal peptide Gabriela Rosas • Marı´a Isabel Ramı´rez • Rosa Linares • Ange´lica Trujillo • Roberto Domı´nguez • Leticia Morales-Ledesma
Received: 21 August 2014 / Accepted: 7 October 2014 Ó Springer Science+Business Media New York 2014
Abstract In vitro the vasoactive intestinal peptide (VIP) stimulates progesterone, androgens, and estradiol secretion, and the effects are time-dependent. The present study analyzed the acute (1 h) and sub-acute (24 h) effects of unilateral injection of VIP into the ovarian bursa on each day of the estrous cycle on progesterone, testosterone, and estradiol serum levels. Cyclic 60-day-old virgin female rats on diestrus-1, diestrus-2, proestrus, or estrus were injected with saline or VIP 10-6 M into the left or right ovarian bursa. One hour after saline injection on each day of estrus cycle, progesterone levels were higher than in control animals. The acute effects of saline solution on testosterone and estradiol levels were asymmetric and varied during the estrous cycle. In comparison with saline groups, the effects of VIPergic stimulation on progesterone, testosterone, and estradiol serum levels depend on the time elapsed between treatment and autopsy and vary during the estrous cycle. An acute asymmetric response from the ovaries to the VIP was observed at diestrus-1, diestrus-2, and proestrus on progesterone and estradiol levels. The asymmetries on testosterone levels were observed at diestrus-1, diestrus-2, and estrus days. The present results suggest that in the cyclic rat, each ovary has different sensitivities to VIPergic
G. Rosas M. I. Ramı´rez R. Linares R. Domı´nguez L. Morales-Ledesma (&) Biology of Reproduction Research Unit, Physiology of Reproduction Laboratory, Facultad de Estudios Superiores Zaragoza, UNAM, AP 9-020, CP 15000 Mexico, D.F., Mexico e-mail: [email protected] A. Trujillo Escuela de Biologı´a, Beneme´rita Universidad Auto´noma de Puebla, Edificio 112A Ciudad Universitaria, CP 72570, Puebla, Mexico
stimulation which depends on the endocrine status of the animal. Keywords VIP Ovarian bursa Asymmetry Estrous cycle Steroid hormone
Introduction In the ovary, the ovulation and steroid hormones secretion are regulated by hormonal and neural signals [1–6]. The ovary receives sympathetic innervation through two neural pathways: the superior ovarian nerve (SON), which travels along the suspensory ligament and the ovarian plexus nerve (OPN) accompanying the ovarian artery [7]. The SON is the main source of sympathetic innervations [8] and provides to the ovary with fibers containing catecholamines and vasoactive intestinal peptide (VIP) [9–11]. The vagus nerve also provides VIPergic innervation to the ovaries [12]. VIP is a 28-amino acid peptide [13]. The VIP-mRNA has been observed in the ovaries of rats [14], and the presence of VIP immuno-reactivity in the granulosa layer of the pre-ovulatory follicles suggests that these cells may be the site wh
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