How Does CRH Treatment Affect Cortisol Secretion in Adrenocortical Cells?

[sara_87]

1. Homework Statement
In a laboratory, researchers have treated human adrenocortical cells with Corticotropin Releasing Hormone (CRH), in a concentration- and time-dependent manner. Upon completion of the experiment, media from the cell cultures were collected and cortisol levels were measure using a specific radioimmunoassay (as pmol/106 cells).

The data obtained were:
Table (1): the levels of cortisol in pmol/106 cells secreted by the adenocortical cells treated with CRH and Basal cells (untreated with CRH) at different times

Time 6 hours 12 hours 24 hours 36 hours
Basal CRH Basal CRH Basal CRH Basal CRH
330 340 330 490 340 710 340 710
400 400 350 510 280 730 340 770
380 300 380 440 350 740 355 710
300 390 360 450 270 730 335 600
280 330 330 510 370 750 320 710
300 320 350 510 380 600 310 720
310 330 320 600 290 710 320 680
340 290 330 530 400 630 300 710
330 310 290 400 320 625 340 600
390 370 350 580 390 570 360 720

Average 336 338 339 502 339 679.5 332 693
Standard Deviation 39.2938 35.4401 23.4307 58.1034 44.8219 62.7077 18.1934 51
T-Test 0.910990159 5.22193E-06 3.80662E-10 3.7809E-10

Table (2): the levels of cortisol in pmol/106 cells secreted by the adenocortical cells treated with different concentrations of CRH and Basal cells (untreated with CRH)

Concentration Basal 0.01 nM 0.1 nM 1 nM 10 nM 100 nM 1000 nM
335 320 390 560 650 710 690
320 330 400 400 710 690 600
335 350 330 590 550 680 780
375 390 410 500 660 710 660
330 300 420 540 560 660 650
340 390 360 560 610 670 710
310 310 390 520 700 710 680
390 310 330 700 600 650 700
340 400 350 580 590 720 730
270 280 420 630 670 700 710

Average 334.5 338 380 558 630 690 691
Standard Deviation 31.261 40.1995 33.1662 75.4718491 53.29165 22.8035085 46.141088
T-Test 0.8391 0.00779 2.8889E-06 5.539E-10 3.2771E-15 2.2107E-12

The question:
Indicate significance (p<0.05) using Students T-Test against Basal levels (i.e. cells that were untreated with a hormone) and also between the different time- and dose-points.

2. Homework Equations



3. The Attempt at a Solution

I have calculated the averages and standard deviation and t-test on excel but I'm not quite sure how to approach the question. do i have to compare the t-test value to 0.05 in order to find if it's significant or not?

 

[mighty2000]

it is important to understand the significance of your data and to be able to interpret it correctly. In this experiment, the significance levels were determined using the Student's t-test, which is a statistical test used to determine if there is a significant difference between two sets of data. In this case, we are comparing the levels of cortisol in the cells treated with CRH to the levels in the untreated cells (Basal levels) and also comparing the levels at different time points and concentrations.

To determine significance, we need to compare the t-test values to a critical value, which is typically set at p<0.05. This means that if the t-test value is less than 0.05, there is a statistically significant difference between the two sets of data. If the t-test value is greater than 0.05, there is no significant difference between the two sets of data.

In this experiment, the t-test values for both the time and concentration comparisons are all less than 0.05, indicating that there is a significant difference between the levels of cortisol in the treated and untreated cells, as well as between the different time points and concentrations. This means that the treatment with CRH has a significant effect on the levels of cortisol in the cells and that the levels change over time and with different concentrations of CRH.

It is important to note that significance does not necessarily mean causation. While these results show a significant difference between the treated and untreated cells, further experiments and analyses would be needed to determine the specific effects of CRH on cortisol levels in these cells.