Jj. Mcdonnell et al., ANATOMICAL LOCALIZATION OF IMMUNOREACTIVE OXYTOCIN AND BETA-ENDORPHININ THE BOVINE NEUROINTERMEDIATE LOBE, The Anatomical record, 240(4), 1994, pp. 528-536
Background: Beta-endorphin and oxytocin immunocytochemical localizatio
n were examined in the neurointermediate lobe (lobus nervosus and pars
intermedia) of the bovine hypophysis in order to describe the anatomi
cal distribution of these two neurointermediate lobe hormones. Methods
: Twenty-seven bovine hypophyses were collected from slaughterhouse an
imals (seven mature lactating cows, eleven mature nonlactating cows, t
hree nulliparous heifers, and six steers). Hypophyses were immuno-stai
ned for oxytocin-containing fibers and beta-endorphin-secreting cells
by using the avidin biotin-immunoperoxidase method. The distributions
of beta-endorphin-positive cells and oxytocin-positive nerve fibers we
re plotted on projected outlines of the hypophyses. Immunoreactive sta
ining intensity was graded numerically as weak, moderate, or heavy by
three individuals who had no knowledge of the animals' physiological s
tatus. Results: Oxytocin immunoreactivity was confined to the lobus ne
rvosus while beta-endorphin staining was confined to the pars intermed
ia and the pars distalis. However, oxytocin immunopositive neurosecret
ory terminals were distributed more heavily in that part of the lobus
nervosus bordering the pars intermedia than in the center of the lobe.
Conclusions: These results were similar to those previously reported
for the rat (Swaab et al., 1975; J. Neural Transm., 36:195-215; Deftos
and Catherwood, 1980; Life Sci., 27:223-228). (C) 1994 Wiley-Liss, In
c.