Immunohistochemical evidence of seasonal changes of gonadotropes in male ruin lizard (Podarcis sicula campestris De Betta)

The pars distalis from thè pituitary gland of adult male ruin lizards (Podarcis sicula campestris De Betta), captured during thè five periods of thè annual sexual cycle (emergence from hibernation, reproductive period, summer regression, autumnal recrudescence, winter arrest), was studied immunohistochemically using specific antibodies against hFSHp, hLHp, oFSHp. and oLHp with thè avidinbiotin complex (ABC) procedure to monitor thè seasonal changes in shape, size and percentage area taken up from gonadotropes. FSH containing cells were specificali}' identified with anti-hFSHp and anti-oFSHp sera, whereas thè LH cells were localized by anti-hLH(3. The anti-oLHp serum showed cross-reactivity with thè cells immunostained by thè three above antisera (anti-hFSHp, anti-oFSHp, and anti-hLHp). None of thè cells contained both gonadotropic hormones as shown by thè doubleimmunostaining procedure. Generally, FSH cells were larger and more numerous than LH cells. FSH cells were elongated or pyriform in shape from spring to autumn. whereas they were round or ovai during thè winter stasis and until thè emergence from hibernation. The size and thè percentage area occupied by FSH cells showed an annual pattern with two distinct peaks in thè reproductive and in thè autumnal recrudescence periods. LH cells did not show seasonal changes in shape, being round or ovai throughout thè reproductive cycle, whereas their size and thè area they occupied underwent seasonal variations. The LH cells reached thè largest size during thè reproductive period and thè smallest size during thè summer regression. The percentage area occupied by LH cells in thè pars distalis peaked at thè emergence from hibernation and during thè summer refractory period, when FSH cells displayed their lowest values.