Engel, K.B. & Callard, G.V. (2005)
The Testis and Spermatogenesis. In W.C. Hamlett (Ed.), Reproductive biology and phylogeny of chondrichthyes: sharks, rays and chimaeras, Vol. 3 (pp. 171–200). Science Publishers, Endfield, USA
Engel, K.B. & Merson, R. & Hahn, M.E. & Callard, G.V. (2005)
Development of the Little Skate (Raja erinacea) as an in situ bioindicator of environmental spermatotoxicants [Abstract]. American Elasmobranch Society 21th Annual Meeting, Tampa, Florida
Betka, M. & Callard, G.V. (1999)
Stage-dependent accumulation of cadmium and induction of metallothionein-like binding activity in the testis of the Dogfish shark, Squalus acanthias. Biology of Reproduction, 60(1), 14–22
DOI: 10.1095/​biolreprod60.1.14
Callard, G.V. & McClusky, L.M. & Betka, M. (1998)
Apoptosis as a normal mechanism of growth control and target of toxicant actions during spermatogenesis: Insights using the Shark Testis Model. In New Developments in Marine Biotechnology. Y. Le Gal and H.O Halvorson(eds.), Plenum Press, New York. pp. 125–128
McClusky, L.M. & Callard, G.V. (1997)
In situ end-labeling of fragmented DNA in apoptotic germ cells in the spiny dogfish (Squalus acanthias) testis. Bulletin of the Mount Desert Island Biological Laboratory, 37, 106–107
McClusky, L.M. & Betka, M. & Miller, D. & Callard, G.V. (1996)
Analysis of the apoptotic form of programmed cell death (PCD) during spermatogenesis in spiny dogfish (Squalus acanthias). Bulletin of the Mount Desert Island Biological Laboratory, 35, 96–97
Piferrer, F.C. & Callard, G.V. (1995)
Inhibition of deoxyribonucleic acid synthesis during premeiotic stages of spermatogenesis by a factor from testis-associated lymphomyeloid tissue in the dogfish shark (Squalus acanthias). Biology of Reproduction, 53(2), 390–398
DOI: 10.1095/​biolreprod53.2.390
Barry, T.P. & Thomas, P. & Callard, G.V. (1993)
Stage-Related Production of 21-Hydroxylated Progestins by the Dogfish (Squalus acanthias) Testis. Journal of Experimental Zoology, 265, 522–532
Dubois, W. & Callard, G.V. (1993)
Culture of Intact SertolilGerm Cell Units and Isolated Sertoli Cells from Squalus Testis. II. Stimulatory Effects of Insulin and IGF-I on DNA Synthesis in Premeiotic Stages. Journal of Experimental Zoology, 267, 233–244
Cuevas, M.E. & Collins, K. & Callard, G.V. (1993)
Stage-related changes in steroid-converting enzyme activities in Squalus testis: synthesis of biologically active metabolites via 3 beta-hydroxysteroid dehydrogenase/isomerase and 5 alpha-reductase. Steroids, 58(2), 87–94
DOI: 10.1016/0039-128X(93)90058-U
Callard, G.V. (1992)
Autocrine and Paracrine Role of Steroids During Spermatogenesis: Studies in Squalus acanthias and Necturus maculosus. Journal of Experimental Zoology, 261, 132–142
Dubois, W. & Callard, G.V. (1991)
Culture of Intact Sertoli/Germ Cell Units and Isolated Sertoli Cells From Squalus Testis: I. Evidence of Stage-Related Functions In Vitro. Journal of Experimental Zoology, 258, 359–372
DOI: 10.1002/jez.1402580312
Dubois, W. & Callard, G.V. (1990)
Shark Testis Model: Stage-Dependent Functions and the Regulation of Spermatogenesis. Journal of Experimental Zoology, Supplement, 4, 142–144
Cuevas, M.E. & Callard, G.V. (1989)
In vitro secretion by Sertoli/germ cell units (spermatocysts) derived from dogfish (Squalus acanthias) testis. Bulletin of the Mount Desert Island Biological Laboratory, 28, 30–31
Dubois, W. & Callard, G.V. (1989)
Role of the sertoli cell in spermatogenesis: TheSqualus testis model. Fish Physiology and Biochemistry, 7(1–4), 221–227
DOI: 10.1007/BF00004710
Callard, G.V. & Mak, P. & Dubois, W. & Cuevas, M.E. (1989)
Regulation of Spermatogenesis: The Shark Testis Model. Journal of Experimental Zoology, Supplement, 2, 23–34
Callard, G.V. & Mak, P. (1988)
Characteristics and stage-dependent distribution of a novel steroid binding protein in the testis of Squalus acanthias. Steroids, 52(4), 359–360
DOI: 10.1016/0039-128X(88)90146-8
Callard, I.P. & Klosterman, L. & Callard, G.V. (1988)
Reproductive Physiology. In T.J. Shuttleworth (Ed.), Physiology of Elasmobranch Fishes (pp. 277–317). Springer-Verlag Berlin Heidelberg
DOI: 10.1007/978-3-642-73336-9_10
Mak, P. & Callard, G.V. (1987)
A novel steroid-binding protein in the testis of the dogfish Squalus acanthias. General and Comparative Endocrinology, 68(1), 104–112
DOI: 10.1016/0016-6480(87)90065-7
Ruh, M.F. & Singh, R.K. & Mak, P. & Callard, G.V. (1986)
Tissue and species specificity of unmasked nuclear acceptor sites for the estrogen receptor of Squalus testes. Endocrinology, 118(2), 811–818
DOI: 10.1210/endo-118-2-811
Pudney, J. & Callard, G.V. (1986)
Sertoli cell cytoplasts in the semen of the spiny dogfish Squalus acanthias. Tissue and Cell, 18(3), 375–382
DOI: 10.1016/0040-8166(86)90057-1
Callard, G.V. & Pudney, J.A. & Mak, P. & Canick, J.A. (1985)
Stage-dependent changes in steroidogenic enzymes and estrogen receptors during spermatogenesis in the testis of the dogfish, Squalus acanthias. Endocrinology, 117(4), 1328–1335
DOI: 10.1210/endo-117-4-1328
Callard, G.V. & Mak, P. (1985)
Exclusive nuclear location of estrogen receptors in Squalus testis. Proceedings of the National Academy of Sciences of the United States of America, 82(5), 1336–1340
Pudney, J. & Callard, G.V. (1984)
Development of agranular reticulum in Sertoli cells of the testis of the dogfish Squalus acanthias during spermatogenesis. The Anatomical Record, 209(3), 311–321
DOI: 10.1002/ar.1092090309
Pudney, J. & Callard, G.V. (1984)
Identification of Leydig-like cells in the testis of the dogfish Squalus acanthias. The Anatomical Record, 209(3), 323–330
DOI: 10.1002/ar.1092090310